[asterisk-commits] res fax: Fix deadlock setting FAXMODE channel variable. (asterisk[13])
SVN commits to the Asterisk project
asterisk-commits at lists.digium.com
Fri Aug 26 17:25:09 CDT 2016
Joshua Colp has submitted this change and it was merged.
Change subject: res_fax: Fix deadlock setting FAXMODE channel variable.
......................................................................
res_fax: Fix deadlock setting FAXMODE channel variable.
ASTERISK-25980 added the FAXMODE channel variable to res_fax.c.
Unfortunately, it also introduced a deadlock potential because
set_channel_variables() which sets FAXMODE can be called during a
masquerade. The ast_channel_get_t38_state() which gets the value used to
set FAXMODE cannot be called with the channel locked. As a result, local
channels can deadlock because of how they must acquire the locks necessary
to operate.
The intent of FAXMODE is for dialplan to know how a fax was transferred
after the fax completes. However, the previous patch sets FAXMODE to the
channel's current T.38 state AFTER the fax has completed and where T.38
may have already disconnected.
* Set FAXMODE based upon T.38 negotiations exchanged either with the fax
applications or the fax framehooks.
ASTERISK-26203
Reported by: Etienne Lessard
ASTERISK-24822
Reported by: David Brillert
ASTERISK-22732
Reported by: Richard Mudgett
Change-Id: Id525747254b64c1efe8b1b5973d52ff9719c2ae1
---
M include/asterisk/res_fax.h
M res/res_fax.c
2 files changed, 43 insertions(+), 13 deletions(-)
Approvals:
George Joseph: Looks good to me, but someone else must approve
Joshua Colp: Looks good to me, approved; Verified
diff --git a/include/asterisk/res_fax.h b/include/asterisk/res_fax.h
index 5119bfa..e88d800 100644
--- a/include/asterisk/res_fax.h
+++ b/include/asterisk/res_fax.h
@@ -20,16 +20,16 @@
#ifndef _ASTERISK_RES_FAX_H
#define _ASTERISK_RES_FAX_H
-#include <asterisk.h>
-#include <asterisk/lock.h>
-#include <asterisk/linkedlists.h>
-#include <asterisk/module.h>
-#include <asterisk/utils.h>
-#include <asterisk/options.h>
-#include <asterisk/frame.h>
-#include <asterisk/cli.h>
-#include <asterisk/stringfields.h>
-#include <asterisk/manager.h>
+#include "asterisk.h"
+#include "asterisk/lock.h"
+#include "asterisk/linkedlists.h"
+#include "asterisk/module.h"
+#include "asterisk/utils.h"
+#include "asterisk/options.h"
+#include "asterisk/frame.h"
+#include "asterisk/cli.h"
+#include "asterisk/stringfields.h"
+#include "asterisk/manager.h"
/*! \brief capabilities for res_fax to locate a fax technology module */
enum ast_fax_capabilities {
@@ -187,6 +187,8 @@
int faxdetect_timeout;
/*! flags used for fax detection */
int faxdetect_flags;
+ /*! Non-zero if T.38 is negotiated */
+ int is_t38_negotiated;
};
struct ast_fax_tech;
diff --git a/res/res_fax.c b/res/res_fax.c
index 67b3af1..b7400fa 100644
--- a/res/res_fax.c
+++ b/res/res_fax.c
@@ -641,6 +641,7 @@
struct ast_fax_session_details *new_details = find_or_create_details(new_chan);
ast_framehook_detach(old_chan, old_details->gateway_id);
+ new_details->is_t38_negotiated = old_details->is_t38_negotiated;
fax_gateway_attach(new_chan, new_details);
ao2_cleanup(new_details);
}
@@ -1439,6 +1440,7 @@
static void set_channel_variables(struct ast_channel *chan, struct ast_fax_session_details *details)
{
char buf[10];
+
pbx_builtin_setvar_helper(chan, "FAXSTATUS", S_OR(details->result, NULL));
pbx_builtin_setvar_helper(chan, "FAXERROR", S_OR(details->error, NULL));
pbx_builtin_setvar_helper(chan, "FAXSTATUSSTRING", S_OR(details->resultstr, NULL));
@@ -1447,7 +1449,7 @@
pbx_builtin_setvar_helper(chan, "FAXBITRATE", S_OR(details->transfer_rate, NULL));
pbx_builtin_setvar_helper(chan, "FAXRESOLUTION", S_OR(details->resolution, NULL));
- if (ast_channel_get_t38_state(chan) == T38_STATE_NEGOTIATED) {
+ if (details->is_t38_negotiated) {
pbx_builtin_setvar_helper(chan, "FAXMODE", "T38");
} else {
pbx_builtin_setvar_helper(chan, "FAXMODE", "audio");
@@ -1656,6 +1658,7 @@
ast_string_field_set(details, result, "");
ast_string_field_set(details, resultstr, "");
ast_string_field_set(details, error, "");
+ details->is_t38_negotiated = t38negotiated;
set_channel_variables(chan, details);
if (fax->tech->start_session(fax) < 0) {
@@ -1706,12 +1709,18 @@
* do T.38 as well
*/
t38_parameters_fax_to_ast(&t38_parameters, &details->our_t38_parameters);
- t38_parameters.request_response = (details->caps & AST_FAX_TECH_T38) ? AST_T38_NEGOTIATED : AST_T38_REFUSED;
+ if (details->caps & AST_FAX_TECH_T38) {
+ details->is_t38_negotiated = 1;
+ t38_parameters.request_response = AST_T38_NEGOTIATED;
+ } else {
+ t38_parameters.request_response = AST_T38_REFUSED;
+ }
ast_indicate_data(chan, AST_CONTROL_T38_PARAMETERS, &t38_parameters, sizeof(t38_parameters));
break;
case AST_T38_NEGOTIATED:
t38_parameters_ast_to_fax(&details->their_t38_parameters, parameters);
t38negotiated = 1;
+ details->is_t38_negotiated = 1;
break;
default:
break;
@@ -2902,6 +2911,7 @@
ast_string_field_set(details, result, "FAILED");
ast_string_field_set(details, resultstr, "error starting gateway session");
ast_string_field_set(details, error, "INIT_ERROR");
+ details->is_t38_negotiated = 0;
set_channel_variables(chan, details);
report_fax_status(chan, details, "No Available Resource");
ast_log(LOG_ERROR, "Can't create a FAX session, gateway attempt failed.\n");
@@ -2922,6 +2932,7 @@
ast_string_field_set(details, result, "FAILED");
ast_string_field_set(details, resultstr, "error starting gateway session");
ast_string_field_set(details, error, "INIT_ERROR");
+ details->is_t38_negotiated = 0;
set_channel_variables(chan, details);
return -1;
}
@@ -2967,6 +2978,7 @@
gateway->t38_state = T38_STATE_NEGOTIATING;
gateway->timeout_start = ast_tvnow();
+ details->is_t38_negotiated = 0;
details->gateway_timeout = FAX_GATEWAY_TIMEOUT;
ast_debug(1, "requesting T.38 for gateway session for %s\n", ast_channel_name(chan));
@@ -3064,6 +3076,7 @@
t38_parameters_ast_to_fax(&details->their_t38_parameters, control_params);
gateway->t38_state = T38_STATE_UNKNOWN;
gateway->timeout_start = ast_tvnow();
+ details->is_t38_negotiated = 0;
details->gateway_timeout = FAX_GATEWAY_TIMEOUT;
ao2_ref(details, -1);
return f;
@@ -3079,12 +3092,14 @@
if (fax_gateway_start(gateway, details, chan)) {
ast_log(LOG_ERROR, "error starting T.38 gateway for T.38 channel %s and G.711 channel %s\n", ast_channel_name(active), ast_channel_name(other));
gateway->t38_state = T38_STATE_REJECTED;
+ details->is_t38_negotiated = 0;
control_params->request_response = AST_T38_REFUSED;
ast_framehook_detach(chan, details->gateway_id);
details->gateway_id = -1;
} else {
gateway->t38_state = T38_STATE_NEGOTIATED;
+ details->is_t38_negotiated = chan == active;
control_params->request_response = AST_T38_NEGOTIATED;
report_fax_status(chan, details, "T.38 Negotiated");
}
@@ -3102,6 +3117,7 @@
t38_parameters_ast_to_fax(&details->their_t38_parameters, control_params);
gateway->t38_state = T38_STATE_UNKNOWN;
gateway->timeout_start = ast_tvnow();
+ details->is_t38_negotiated = 0;
details->gateway_timeout = FAX_GATEWAY_TIMEOUT;
ast_debug(1, "%s is attempting to negotiate T.38 after we already sent a negotiation request based on v21 preamble detection\n", ast_channel_name(active));
@@ -3124,6 +3140,7 @@
ast_string_field_set(details, result, "SUCCESS");
ast_string_field_set(details, resultstr, "no gateway necessary");
ast_string_field_set(details, error, "NATIVE_T38");
+ details->is_t38_negotiated = 1;
set_channel_variables(chan, details);
ast_debug(1, "%s is attempting to negotiate T.38 after we already negotiated T.38 with %s, disabling the gateway\n", ast_channel_name(active), ast_channel_name(other));
@@ -3138,6 +3155,7 @@
&& control_params->request_response == AST_T38_REFUSED) {
ast_debug(1, "unable to negotiate T.38 on %s for fax gateway\n", ast_channel_name(active));
+ details->is_t38_negotiated = 0;
/* our request to negotiate T.38 was refused, if the other
* channel supports T.38, they might still reinvite and save
@@ -3166,11 +3184,13 @@
if (fax_gateway_start(gateway, details, chan)) {
ast_log(LOG_ERROR, "error starting T.38 gateway for T.38 channel %s and G.711 channel %s\n", ast_channel_name(active), ast_channel_name(other));
gateway->t38_state = T38_STATE_NEGOTIATING;
+ details->is_t38_negotiated = 0;
control_params->request_response = AST_T38_REQUEST_TERMINATE;
fax_gateway_indicate_t38(chan, active, control_params);
} else {
gateway->t38_state = T38_STATE_NEGOTIATED;
+ details->is_t38_negotiated = chan == active;
report_fax_status(chan, details, "T.38 Negotiated");
}
@@ -3186,14 +3206,16 @@
t38_parameters_fax_to_ast(control_params, &details->our_t38_parameters);
if (fax_gateway_start(gateway, details, chan)) {
- ast_log(LOG_ERROR, "error starting T.38 gateway for T.38 channel %s and G.711 channel %s\n", ast_channel_name(active), ast_channel_name(other));
+ ast_log(LOG_ERROR, "error starting T.38 gateway for T.38 channel %s and G.711 channel %s\n", ast_channel_name(other), ast_channel_name(active));
gateway->t38_state = T38_STATE_REJECTED;
+ details->is_t38_negotiated = 0;
control_params->request_response = AST_T38_REFUSED;
ast_framehook_detach(chan, details->gateway_id);
details->gateway_id = -1;
} else {
gateway->t38_state = T38_STATE_NEGOTIATED;
+ details->is_t38_negotiated = chan == other;
control_params->request_response = AST_T38_NEGOTIATED;
}
@@ -3209,6 +3231,7 @@
details->gateway_id = -1;
gateway->t38_state = T38_STATE_REJECTED;
+ details->is_t38_negotiated = 0;
control_params->request_response = AST_T38_TERMINATED;
fax_gateway_indicate_t38(chan, active, control_params);
@@ -3224,6 +3247,7 @@
ast_string_field_set(details, result, "SUCCESS");
ast_string_field_set(details, resultstr, "no gateway necessary");
ast_string_field_set(details, error, "NATIVE_T38");
+ details->is_t38_negotiated = 1;
set_channel_variables(chan, details);
ao2_ref(details, -1);
@@ -3351,6 +3375,7 @@
ast_string_field_set(details, result, "FAILED");
ast_string_field_set(details, resultstr, "neither channel supports T.38");
ast_string_field_set(details, error, "T38_NEG_ERROR");
+ details->is_t38_negotiated = 0;
set_channel_variables(chan, details);
return f;
}
@@ -3395,6 +3420,7 @@
ast_string_field_set(details, result, "FAILED");
ast_string_field_build(details, resultstr, "no fax activity after %d ms", details->gateway_timeout);
ast_string_field_set(details, error, "TIMEOUT");
+ details->is_t38_negotiated = 0;
set_channel_variables(chan, details);
return f;
}
@@ -3525,6 +3551,7 @@
ast_string_field_set(details, result, "FAILED");
ast_string_field_set(details, resultstr, "error initializing gateway session");
ast_string_field_set(details, error, "INIT_ERROR");
+ details->is_t38_negotiated = 0;
set_channel_variables(chan, details);
report_fax_status(chan, details, "No Available Resource");
return -1;
@@ -3540,6 +3567,7 @@
ast_string_field_set(details, result, "FAILED");
ast_string_field_set(details, resultstr, "error attaching gateway to channel");
ast_string_field_set(details, error, "INIT_ERROR");
+ details->is_t38_negotiated = 0;
set_channel_variables(chan, details);
return -1;
}
--
To view, visit https://gerrit.asterisk.org/3710
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Gerrit-MessageType: merged
Gerrit-Change-Id: Id525747254b64c1efe8b1b5973d52ff9719c2ae1
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-Owner: Richard Mudgett <rmudgett at digium.com>
Gerrit-Reviewer: Anonymous Coward #1000019
Gerrit-Reviewer: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Joshua Colp <jcolp at digium.com>
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